Package org.apache.juneau.commons.collections

Class FluentSet<E>

java.lang.Object
java.util.AbstractCollection<E>
java.util.AbstractSet<E>
org.apache.juneau.commons.collections.FluentSet<E>
Type Parameters:
E - The element type.
All Implemented Interfaces:
Iterable<E>, Collection<E>, Set<E>
public class FluentSet<E> extends AbstractSet<E>
A fluent wrapper around an arbitrary set that provides convenient methods for adding elements.

This class wraps an underlying set and provides a fluent API for adding elements. All methods return this to allow method chaining. The underlying set can be any Set implementation.

Features:
  • Fluent API: All methods return this for method chaining
  • Arbitrary Set Support: Works with any set implementation
  • Conditional Adding: Add elements conditionally based on boolean expressions
  • Transparent Interface: Implements the full Set interface, so it can be used anywhere a set is expected
  • Automatic Deduplication: Duplicate elements are automatically handled by the underlying set
Usage:

// Create a FluentSet wrapping a LinkedHashSet FluentSet<String> set = new FluentSet<>(new LinkedHashSet<>()); set .a("item1") .a("item2") .ai(true, "item3") // Added .ai(false, "item4"); // Not added // Add all elements from another collection Set<String> other = Set.of("item5", "item6"); set.aa(other);

Example - Conditional Building:

boolean includeDebug = true; boolean includeTest = false; FluentSet<String> set = new FluentSet<>(new LinkedHashSet<>()) .a("setting1") .a("setting2") .ai(includeDebug, "debug") // Added .ai(includeTest, "test"); // Not added

Behavior Notes:
  • All set operations are delegated to the underlying set
  • The fluent methods (a(Object), aa(Collection), ai(boolean, Object)) return this for chaining
  • If a null collection is passed to aa(Collection), it is treated as a no-op
  • The underlying set is stored by reference (not copied), so modifications affect the original set
  • Duplicate elements are automatically handled by the underlying set (only one occurrence is stored)
Thread Safety:

This class is not thread-safe unless the underlying set is thread-safe. If thread safety is required, use a thread-safe set type (e.g., CopyOnWriteArraySet).

See Also: